Augusta Adams Cobb Young (Brigham Young's 2nd plural wife) wrote out what she called her "Last Will and Testament" (She did not die until 1886,) a request to cancel her sealing for eternity (but not for time) to Brigham Young so she could be sealed by proxy to either Jesus Christ (her first priority) or Joseph Smith. She ended her request, "I do this in the name of the Lord Jesus Christ and by virtue of the Holy Priesthood vested in me, because I consider it necessary to my salvation, exaltation, calling and Election." The "will" was witnessed and signed by Heber C. Kimball and Willard Richards (First Presidency).
Brigham Young rejected her several requests to be sealed to Jesus Christ but did cancel their sealing for eternity and stood as proxy as Joseph Smith for her sealing on April 14, 1848.
[Source: Letter, O'Donovan, Connell, "Augusta Adams Cobb Young: Priesthood Holder," Journal of Mormon History Vol. 38, No. 2, Spring 2012]